Automatic lamp base threading machine



June 5, 1956 J. FLAWS, JR.. ET AL 2,743,450

AUTOMATIC LAMP BASE THREADING MACHINE I 4 Sheets-Sheet 1 Filed June 30, 1951 y w: v

s ww v] 5 00 Q wiw m ha 0 FR KL n m M u m %R e h m r T e Cb June 5, 1956 .1. FLAWS, JR., ET AL 2,748,450

AUTOMATIC LAMP BASE THREADING MACHINE Filed June 30, 1951 i 4 Sheets-Sheet 2 Inventors- John Flaws, Jr. Kenneth W Reynolds Cad R. MecKstroth byM W 4 Them Attorney June 5, 1956 J, FLAWS, JR., ET AL 2,748,450

AUTOMATIC LAMB BASE THREADING MACHINE Filed June 50, 1951 4 Sheets-Sheet 3 Inventors: John Flaws, Jr. Kenneth W Reynolds Cad R. MecKstroth yM I Thenr Attorney June 5, 1956 I J. FLAWS, JR, ET AL 2,748,450

AUTOMATIC LAMP BASE THREADING MACHINE Filed June 50, 1951 4 Sheets-Shet 4 Inventors;

John Fiaw's, Jr. Kenneth W Reynolds Ca r\ R. MecKstroth I Then" Attorney Figs. a and 5b are sectional plan views of the base I threading tube of Fig. 4, shown in its closed and open positions respectively.

Fig. 6 is a pictorial view of another embodiment of our invention wherein the vibration of the base is achieved by magnetic induction.

Fig. 7 is a pictorial view of yet another embodiment of our invention wherein the vibration of the base is achieved by mechanical means.

The problems involved in basing an electric lamp may be understood by reference to Fig. l which shows the component parts of an incandescent lamp of a common type, prior to the basing and final assembly. The glass bulb 1 is of a pear shape and has a constricted upper neck portion 2 out of the center of which extend the lead-in wires 3 and 4. The inward projections of the lead-in wires support the filament 5 within the bulb, the section of the lead-in wires extending through the press 6 being of the usual dumet type. The base 7 comprises a threaded metallic shell 8 whereof the upper end is closed by a web 9 of insulating material such as glass, which web is capped by an end contact formed by a metal eyelet 10. The eyelet has a central hole through which the top lead-in wire is threaded during the basing operation in order to permit a solder connection to be made at that point. Immediately below the eyelet hole, the web 9 is recessed to a generally conical shape as may be seen at 11; the purpose of this configuration is to facilitate threading the top wire through the eyelet hole. The lower flare of the shell 8 has an annular ring of cement internally disposed within it as may be seen at 12; after setting, the cement assures a firm adhesion between the base and the bulb.

When the bulb is manually based, the first step performed by the operator consists in pulling the top wire 3 vertically upwards, and the side wire 4 laterally downwards so that its lies quite close to the neck of the bulb. Thereafter the operator takes a base, and, after locating it approximately over the bulb so that the eyelet hole and the top wire are in line, proceeds to thread it. Although it may be thought at first sight that, immediately the wire 3 has been located anywhere within the conical recess 11 in the web of the base, the base would invariably be threaded merely by pressing down upon it, such is not the case. The top wire 3 is quite fine and fragile, and very often the web 9 and the conical recess 11 have irregularities in their surfaces and are far from being perfectly smooth.

The lead-in wire may catch in one of these irregularities and if the operator were merely to apply more pressure, it would bend over and not enter the eyelet hole. Thus the operator proceeds largely on a trial and error basis and if it should be felt that the top wire is catching on the web, the base is withdrawn slightly and another attempt made at a slightly different position. Sometimes even though the threading operation has been successful, the top wire 3 may have been forced down and bent slightly, in which case it might contact the side wire 4 and the finished lamp would be useless. In order to avoid such a possibility, after the threading operation has been performed, the operator pulls up the lead wire tautly through the eyelet hole in order to take up any slackness.

The base threading machine in accordance with our invention performs automatically the above described basing operation, and does so substantially on a trial and error basis in the same fashion as in manual threading. The machine may be supplied with bases and bulbs by hand and will automatically locate the bases on the neck of the bulb and will thread the top lead-in wire through the eyelet hole. However, in common with most automatic lamp making machinery, it is preferably 0perated in conjunction with a suitable conveyor system whereby the machine is automatically supplied with the bulb assemblies and with the bases at the proper. rate and under the required conditions. Such a machine is illustrated in simplified schematic outline in Fig. 2, wherein there is shown an elongated oval track 15 around which lamp holding chucks 16 are driven by means of a roller chain 17. The roller chain engages at opposite extremities a pair of sprockets 18 and 19. The former is the driving sprocket and it is rotated through predetermined angles at equal time intervals by means of the Geneva drive gearing shown generally at 20 and comprising the slotted disc 21 driven by the pin and segment gear 22. Sprocket 19 is free turning and serves merely to guide the chain.

The details of a lamp holding chuck may be seen more readily in Fig. 3. The chuck assembly 16 comprises a generally rectangular shaped base 21 on which are pivotally mounted a pair of jaws 22 and 23. These jaws are secured to a pair of cranks 24 and 25 which are spring biased with respect to the base by means of springs 26 and 27. The jaws are thus normally urged together to a substantially upright position in a manner to engage opposite sides of a lamp bulb and to seat it firmly on the crowfoot-shaped cup 28. The bulb may be released by bearing down on the projecting cross portions of cranks 24 and 25 in order to pivot jaws 22 and 23 back.

The chuck assemblies are driven by the roller chain 17 of which a portion is shown, for greater clarity, downwardly displaced below the chuck, that is, in exploded relation. A pair of adjoining rollers have elongated pins '29 and 30 which are fastened to the chuck base 21 so that the chuck assembly as a whole behaves as one of the links of the chain. During the travel of the chuck along the straight portions of the track between the sprockets 18 and 19, it is kept in alignment by means of rollers 31 secured to its underside by spindle bolts 32 and bearing against the guide rail or track 15. The wedge-shaped guard plates 33 and 34 which, as may be seen in Fig. 2, are overlapped with respect to the guard plates of the chuck next in line on the conveyor, are provided for the purpose of preventing debris such as glass fragments from falling on the chain and interfering with its operation.

Referring once again to Fig. 2, the conveyor system has 16 stations which are denoted consecutively by A through -P. There are of course 16 chuck assemblies mounted on the roller chain and each one passes consecutively through each .one of the 16 indexing station-s.

In the operation of our automatic lam-p threading machine, the bulb assemblies may be manually located in the chucks at some loading position such as station A. However, if completely automatic operation is desired, a bulb loading mechanism may be employed. For instance there is shown at station A, a loading mechanism comprising a vertical chute or tube 36; the bulbs 1 are dropped into the upper end of the tube, preferably by means of a transfer mechanism from the sealing ma chine, and are released, one at a time into the holding chuck located below the tube. The release of the bulb Y may be effected through an escapement mechanism such as a fast acting latch 37 whose movement is controlled by the solenoid 38. It will be understood of course that the jaws of the chuck assembly are pivoted open at this station in order to receive the bulb when it is released from the chute.

With-regards to the unloading of threaded base and lamp assemblies from the conveyor, this may be performed manually at some station such as 1. However in order to achieve automatic operation, a transfer mechanism such as is shown generally at 39 may be employed. The mechanism comprises a pair of gripping jaws 40 pivotal-1y mounted on a crosshead 41 which is adapted to translate on the inclined guide rods 42. The gripping jaws 41 carry the bulb out of the chuck, whose holding jaws are open at station I, and transfer it to a holder on the turret of the finishing machine. It will be understood of course that a suitable mechanical linkage such as a cam actuated connecting rod may be provided for effecting the required translation of-the crosshead.

In addition certain other mechanisms'maybe employed in conjunction with the presently disclosed base threading machine and conveyor system. These additional mechanisms are only necessary where completely automatic operation is desired and where it is also 'desiredto protect against the passage of defective lamps by the machine. It will be understood that where the bulbs are manually fed into the chucks, the operator likewise being available to detect defective lamps, these additional mechanisms may be dispensed with. One-of these mechanisms is a side wire locator and its function is to rotate the bulb in the chuck until the side lead-in wire achieves a predetermined orientation that various other mechanisms may operate upon it, and also in order that the bulb have a definite orientation when finally it is transferred into the finishing machine. For a complete description of this mechanism, reference may be had to the copending application of Kenneth W. Reynolds entitled Side Wire Locating Mechanism, Serial No. 234,595, filed June 30, 1951, now Patent No. 2,683,521 granted July 13, 1954, and assigned to the same assignee as the present invention.

Another mechanism may be used for removing, from the conveyor system, lamps which are defective in having either a missing lead-in wire or a broken filament. This mechanism may be located at station E and for a complete description thereof, reference may be had to the co'pending application of John Flaws, Jr. and C. R. Meckstroth entitled Defective Lamp Detecting and Ejecting Mechanism, Serial No. 234,594, filed June 30, 1951, now Patent No. 2,653,711 granted September 29, 1953, and assigned to the same assiguee as the present invention.

Another mechanism may be provided for insuring that the top wire is pulled up straight and vertical. This mechanism may be located at station F and for a complete description thereof, reference may be had to the copending application of Carl R. Meckstroth and Clarence S. Terez, entitled Top Wire Positioning Mechanism, Serial No. 234,596, filed June 30, 1951, now Patout No. 2,711,760 granted June 28, 1955, and assigned to the same assignee as the present invention.

A particular feature of the present invention is the automatic threading apparatus located at station G and indicated generally at 45. A lamp bulb, held in a chuck such as has been described with reference to Fig. 3, arrives at station G by displacement from the left, as indicated by the arrow 46 in Fig. 2. The bases are fed into the machine from a reserve thereof indicated generally at 47 and located in a fiat inclined trough 48. The vertical side walls 49 of the trough converge together towards the lower end thereof in order to funnel the bases onto the upper side of a distributing disc 51 The function of disc 50 is to feed the bases into the upper end of a slide 51 to the extent required to keep it continually supplied with bases. The disc is of a thickness comparable to the height or axial dimension of the bases and has U-shaped cavities 52 cut into its periphery of a size suitable for accommodating a single base. The bases enter the U-shaped cavities of the disc as it revolves, and drop out :of the cavities into the slide whenever a vacancy occurs in it; if the slide is full, the bases merely continue rotating with the disc and none are fed into it. The disc is driven at a suitable speed by the shaft 53 which may be geared to the motor driving the conveyor system.

The details of a preferred embodiment of a base threading machine of the pneumatic type may be seen more readily in Fig. 4 wherein part of the slide 51 previously described has been cut'away for greater clarity. The bases 7 shown at the upper end of the slide have been fed to it by the distributing disc and trough arrangement previously described with reference to Fig. 2. The side walls of the slide are curved inwards and meet at the lower end thereof, as indicated at '54, thereby forming an end chamber out of which a base may drop into the base threading tube 55. The base threading tubeis constitutedby'two semi-cylindrical members 56 and 57 which are hinged at 5 8 and 59 to a bracket or standard 60 fixed to the bed plate of the conveyor system. The members 56 and 57 are pivoted together to form the threading tube, by the operation of the connecting rods 61 and 62 which are linked to a crank 63. Crank 63 is hinged at 64 onto the standard 60 and is rocked back and forth by suitable cam means coupled to the driving means for the conveyor system. The semi-circular members 56 and 57 have holes drilled into their sides to which compressed air 'iS Supplied through flexible tubes 65 in order to oscillate the base in the tube until the top lead-in wire finds the threading hole.

The operation of the base threading tube may be understood more readily by reference to Figs. 5a and 5b. In Fig. 5a, the semi-cylindrical members 56 and 57 are shown in their closed position for constituting threading tube 55. It will be understood that the threading tube is closed after a 'bulb has been indexed into the base threading station, and that it is necessary to pivot these members open at other times in order to permit the bulbs to enter and leave the threading station without obstruction.

In Fig. 5a, which is a plan view of the semi-cylindrical members 56 and 57, the four upper air holes 66 are shown in dotted outline. These holes are inclined to the radius at the points where they penetrate the inner wall of the threading tube. This disposition provides a tangential component to the air jets and causes the base to rotate or spin in the tube at the same time as it oscillates during the threading operation. If desired, the air may be admitted in intermittent pufis in order to vibrate or oscii'late 'the base more effectively.

The lower air holes 67, which may be seen in Fig. 5b wherein the semi-cylindrical members are shown in section, enter the threading tube radially but are inclined upwardly. As illustrated in Fig. 5a, the threading tube achieves a relatively close fit about the base 7 and the neck of the bulb 1, although there is no actual contact between them. This arrangement provides a partial trapping of air below the base which serves to support or float the base to a certain extent and retards its descent towards the bulb, thereby facilitating the threading of the top wire through the eyelet hole.

In Fig. 5b, the threading tube is shown in its open position, the members 56 and 57 having been outswivelled through the withdrawal of the connecting rods 61 and 62. The out-swivelling of these members clears the path for the movement of the bulbs on the articulated conveyor and allows the indexing of a new bulb into the threading station.

The release of a base from the lower end of the slide 51 into the threading tube 55 at the proper in'stant of time is brought about by the operation of the tongue 70 and of the latches 71 and '72 (Fig. 4). In their closed positions, these members block the opening in the lower end of the slide. Tongue 70 is directly connected to the slidable armature 73 of a solenoid 74; latches 71 and 72 are pivotally mounted on the underside of the slide by pins, as may be seen at 75, and are connected to the armature by toggle links 76 and 7'7. When solenoid 74 is energized, armature 73 moves back, drawing with it tongue 70 and at the same time causing the forward ends of latches 71 and 72 to pivot outwardly, thereby allowing a base to fall through. It will be understood thatthe operation of the solenoid is controlled to occur at the appropriate instant of time in the index cycle of the system through the application of voltage across terminals in known manner. if desired, a switch 79 may be provided in series with the solenoid. The switch is closed when the feeler 80 is pushed back by a bulb held in the chuck indexed into the base thread- '7 ing station. If an empty chuck should arrive, switch 79 remains open and solenoid 74 is not energized so that a base is not released.

In order to insure that no more than one base be released .into the threading tube at each index cycle of the machine, there is provided a unit release mechanism comprising a pivotable lever 31 which is hinged on projecting portion 32 at the lower end of slide 51. This lever is connected through a crank 83 and a connecting rod 84 to a projecting portion 85 of the crank 63. When crank 63 is pivoted forward in a manner to close the threading tube, lever 81 is simultaneously pivoted forward so that its lower end engages the next of the lower-most base in the slide and prevents it, and all the other bases above it, from moving down into the threading position. Thus when the latch release mechanism 70, 71, 72 operates, only the lower-most base is allowed to fall through. At the next index of the mechanism, when the threading tube .is opened and the latch release mechanism is closed, lever 81 is pivoted back and allows the bases to move down the slide.

Referring to Fig. 6, there is shown another embodiment of our invention wherein the vibration of the base, for the purpose of threading it onto the top lead-in wire of the bulb, is achieved by magnetic induction. The bases 7 are dropped into the circular opening 87 formed between the three inwardly facing poles 88 to 90 of a soft iron yoke 91. Yoke 91 is vertically reciprocable on a guide rod 92 and its movement is controlled by means of a link 93 and a crank 94. The operation of the crank is governed in the usual manner by a suitable linkage to the driving means for the conveyor system. A base may be released at the proper instant of time into the opening 87 by a mechanism similar to that which has been described with reference to Fig. 4.

The vibration and rotation of the base 7 is achieved by developing a rotating magnetic field in the opening 87. This may be done by applying three-phase alternating current to the windings 95 to 97 on the poles 87 to 90. Although the base is normally made of some nonmagnetic material such as copper or aluminum, the fact that it is a conductor causes eddy currents to be generated in it through its presence in a rotating magnetic field. These eddy currents cause the base to vibrate and to rotate with the magnetic field and also its rate of descent through the opening 87 is retarded. Thus the base is vibrated in a manner very similar to that occurring with the pneumtaic threading tube described with reference to Fig. 4, and the top lead-in wire is threaded through the eyelet hole on a trial and error basis in substantially the same manner.

Referring to Fig. 7, there is shown yet another embodiment of our invention wherein the base is threaded on the bulb as a result of direct agitation by mechanical means. The apparatus comprises a base 98 which is vertically reciprocable on the slide rod 92 as with the device of Fig. 6. A threading tube 99 is resiliently mounted on the base and supported by means of flexible spring fingers 100, ltll. A magnetic vibrator unit 102 is fixed to the base and its magnetic circuit is completed through an armature 103 attached to the threading tube. The spring fingers and the threading tube are arranged to be mechanically resonant at some frequency close to the frequency of the current with which the vibrator is energized. The threading tube is vertically slotted at equidistant intervals as shown at 104, and flexible snubber wires or springs 105 are located in the slots, being fixed to the tube immediately above the slots. When a base is dropped into the upper end of the tube, the mechanical vibration of the tube causes the base to be buffeted between the snubber wires and its descent is retarded. Thus the threading of a base onto the top lead-in wire of a bulb is achieved on a trial and error basis in similar fashion to what has been described before.

7 While certain specific embodiments have been shown and described, it will of course be understood that various modifications may be made without departing from the invention. The pneumatic base threading mechanism which has been described constitutes the preferred embodiment of our invention. We have also described other base threading mechanisms embodying our invention, one of which operates on the electro-magnetic induction principle and the other of which operates through direct mechanical vibration. It will be realized that these various mechanisms include the common feature of vibrating the base so that in eifect the top wire of the bulb is provided with a great many opportunities for finding the threading hole through the eyelet of the base. Preferably the base is also retarded in its descent down the threading tube so that it bears more lightly on the top wire than if it were allowed to fall freely and the threading is thereby facilitated. Thus these mechanisms duplicate substantially the trial and error procedure which an operator follows in manually threading a base upon a bulb and in putting the top wire through the threading hole. The appended claims are therefore intended to cover any modifications of these mechanisms coming within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. An automatic base threading mechanism for incandescent lamp bulbs, comprising means for holding a bulb in upstanding position with its top lead-in wire substantially vertical, a vertical threading tube for locating a base approximately in cooperating alignment over said bulb, means receiving a base open end down and releasing it into said tube, and means for blowing air into said tube thereby to agitate said base in order to provide repeated opportunities for said lead-in wire to enter the threading hole in the upper surface of said base.

2. An automatic base threading mechanism for incandescent lamp bulbs comprising means for holding a bulb in upstanding position with its top lead-in wire substantially vertical, a tube having an internal bore sufiicient to allow the unimpeded descent of a base therethrough, means for positioning said tube over the neck of said bulb, means receiving a base open end down and releasing it into the upper end of said tube, said tube having lateral openings in its walls, and means for blowing air into said openings thereby to agitate said base while located within said tube, in order to provide repeated opportunities for said lead-in Wire to find and enter the threading hole in said base.

3. An automatic base threading mechanism for incandescent lamp bulbs comprising means for locating a bulb in upstanding position with its top lead-in wire substantially vertical, a vertical threading tube constituted by a pair semi-cylindrical members hinged for swivelling together in order to encompass the neck of said bulb, means receiving a base open end down and releasing it into the upper end of said tube, said sections having openings leading to the internal surface thereof, and means for blowing air into said openings thereby to agitate said base while located within said tube in order to provide repeated opportunities for said lead-in wire to enter the threading hole within the base.

4. In combination, a conveyor system for indexing incandescent lamp bulbs to a base threading station in upstanding position with their top lead-in wires substantially vertical, a vertical threading tube having an internal bore sufficient to allow the unimpeded descent of a base therethrough, means for locating said tube over the neck of a bulb indexed into said station, means receiving a base open end down and releasing it into the upper end of said tube, said tube having lateral openings in its walls, and means for blowing air into said openings thereby to agitate said base while located within said tube, in order to provide repeated opportunities for said lead-in wire to find and enter a threading hole in said base.

5. In combination, a conveyor system for periodically indexing incandescent lamp bulbs to a base threading station in upstanding position with their top lead-in Wires substantially vertical, a vertical threading tube constituted by a pair of hinged semi-cylindrical members, means for swivelling said members together for encompassing the neck of a bulb at said station, means for releasing a base into the upper of said tube, said base being vertically disposed with its open end down and its threading hole up, said sections having openings leading to the internal surface thereof, and means for blowing air into said openings, thereby to agitate and float said base While located Within said tube, in order to provide repeated opportunities for said lead-in wire to enter the threading hole in the base.

6. The method of threading a base on the neck of an incandescent lamp bulb, said base having a threading hole References Cited in the file of this patent UNITED STATES PATENTS Uber June 14, 1938 Kew et al May 14, 1946 

